ThmDex – An index of mathematical definitions, results, and conjectures.
F5148
Formulation 0
Let $X$ be a D11: Set such that
(i) $\mathcal{P}(X)$ is the D80: Power set of $X$
(ii) $E \in \mathcal{P}(X)$
Then \begin{equation} X \setminus E \in \mathcal{P}(X) \end{equation}